Drawing apparatus



March 16, 1965 c. H. BEAN DRAWING APPARATUS Filed June 8, 1962 INVENTOR. Ckarlesflfv'e an anlliiiiisavi I United States Patent Ofi lice 3,173,284 Patented Mar. 16, 1965 3,173,284 DRAWING APPARATUS (Iharles H. Bean, Naperville, IlL, assignor to the United States of America as represented by the United States Atomic Energy Commission Filed June 8, 1962, Ser. No. 201,223 1 Claim. (Cl. 72283) This invention relates to an apparatus for drawing long metallic rods or tubes, and more particularly, to an arrangement of such a drawing apparatus enabling the overall length thereof to be held down.

Drawing apparatuses are well known in which the movement of a workpiece through a drawing die is produced by relative movement between a piston and a pressure-fluid cylinder. With such an apparatus the over-all length is about three times the length of the workpiece being drawn. Thus, if a long tube or rod is being drawn, a large space in a shop must be provided to accommodate the apparatus.

An object of the present invention is to provide an improved drawing apparatus in which the over-all length is held down.

A further object is the provision of an improved drawing apparatus in which a workpiece is pulled by a pressure-fluid cylinder and piston.

Gther objects will appear from the following description and the attached drawing, in which:

FIG. 1 is an elevation, partly in section and a schematic showing, of the novel drawing apparatus 'of the present invention;

FIG. 2 is a sectional view taken on the line 2-2 of FIG. 1;

FIG. 3 is a fragmentary view, partly in section, showin the mounting for a workpiece gripper on an hydraulic cylinder; and

FIG. 4 is a sectional view taken on the line 44 of FIG. 3.

The novel drawing apparatus of the present invention comprises an elongated frame 10, a drawing die 11 mounted at about the midpoint of the length of the frame 10, a fixed piston 12 also mounted at about the midpoint of the length of the frame 11 a movable cylinder 13 axially shiftable lengthwise of the frame 10, and a gripper 14 for pulling a workpiece 15 through the die 11, the gripper being attached to one end of the cylinder 13 so that the workpiece extends in parallel side-by-side relationship to the cylinder 13. Thus, the frame 16' need be only about twice as long as the workpiece 15.

In the example shown, the workpiece being reduced by the drawing die 11 is a tube and is carried on a mandrel 16 having at its free end an enlarged plug 17 for internally supporting the workpiece at the region passing through the drawing die 11.

The frame 10 essentially comprises a pair of side members 18 in the form of long shallow channels and a pair of end pieces 19 secured by welding or the like to the side members 18 to hold them in spaced parallel relationship. The frame 10 is horizontally supported above and in spaced relation to the fioor by means of a plurality of pairs of legs 20, which are secured as by welding or the like at their upper ends to the side members 18 and have at their lower ends support shoes 21, which may be bolted to the floor. The legs 20 of each pair are braced by horizontal cross pieces 22 secured by welding or the like to the legs just above the support shoes 21.

The piston 12 is fixed with respect to the frame 10 by being secured at about the midpoint of a rod 23 which is secured to the end pieces 19 of the frame. The rod 23 extends through the piston 12 and between the side members 18 of the frame and has threaded ends passing through the end pieces 13. Nuts 24 on the ends of the rod 23 bear against the end pieces 19 and place the rod under tension.

The cylinder 13, which tightly embraces the piston 12, is mounted for axial movement with respect to the frame 10 by means of a pair 'of opposed longitudinal shoes 25 secured to the cylinder and a pair of opposed longitudinal ways or gibs 26 engaging the shoes 25 and secured to the inner faces of the side members 18. The shoes 25 are secured by welding or the like to the cylinder 13, extend substantially the entire length thereof, and have tongues 27 fitting grooves on the ways 26 so as to support the cylinder 13 vertically. The ways 26 extend substantially the entire length of the side members 18 and are secured thereto by welding or the like with spacing elements 27a therebetween.

The gripper 14, which essentially comprises relatively movable jaws 28 and an actuator 29 for regulating the jaws, is attached to one end of the cylinder 13 by a structure 30. This structure comprises a horizontal top piece 31 to which the gripper 14 is directly fastened, as by bolting or welding, a vertical longitudinal piece 32; a pair of vertical cross pieces 33 secured to opposite sides of the piece 32, the top piece 31 and the cylinder 13; and a vertical end piece 34 secured to the top piece 31, longitudinal piece 32, and the cylinder 13. The securement just described is by welding or the like. The end piece 34 lies against the transverse end surface of the cylinder 13 and has an opening 35 through which the rod 23 passes.

The die 11 is mounted at a midregion of the frame 10 by being detachably connected to a head 36 secured to the frame 11] by welding or the like.

The end of the mandrel 16 remote from the plug 17 is joined in a pivotal connection 37 to a short rod 38 secured to a piston 33 slidably mounted in a doubleacting fluid-pressure cylinder 40. The pivotal connection 37 permits the mandrel 16 to be swung upwards to the broken-line position of FIG. 1 for clearing the die 11 so that the workpiece 15 maybe slipped on the mandrel. The cylinder 40, which is relatively short, is secured to one end of the frame by a bracket 40a.

The piston 39 and cylinder 49 move the mandrel 16 axially so that the mandrel plug 17 fitting within a reduced end 41 on the workpiece 15 moves the workpiece to bring the reduced end partially through the die 11 so that it can be engaged by the gripper 14. When the gripper first engages the reduced end 41 of the workpiece 15, the gripper will be somewhat to the left of its brokenline position of FIG. 1. When there is no workpiece 15 on the mandrel 16, it rests, as shown in FIG. 1, on a support 41a and a roller 41b of a support 410, the supports being attached to the upper edges of the member 18. When the mandrel 16 has received the workpiece 15, the latter engages the support 41a and roller 41b.

The piston 39 is moved in one direction or the other in the cylinder 40 by pressure fluid such as oil supplied thereto by lines 42 and 43 connected by a 4-way 3-position valve 44 with pressure and exhaust lines 45 and 46 of a pump 47. In the position of the valve 44 shown in FIG. 1, the pressure and exhaust lines 45 and 46 of the pump 47 are connected with one another so as to bypass the cylinder 40, and the piston 39 is held against movement because pressure fluid is neither supplied to nor exhausted from the lines 42 and 43. When the valve 44 is rotated counterclockwise, from the position of FIG. 1, it connects the left end of the cylinder 40 with the pressure line 45 through the line 42 and the right end of the cylinder with the exhaust line 46 through the line 43, and so the piston 39 moves to the right. When the valve 44 is rotated clockwise from the position of FIG. 1, the right end of the cylinder 40 is connected with the pressure line 45 through the line 43, and the left end of the cylinder is connected with the exhaust line 46 through the line 42; consequently, the piston 39 moves to the left. At the start of a drawing operation, the piston 39 is moved to the right to insert the mandrel plug 17 in the die 11. At the end of a drawing operation, the piston 39 is moved to the left so that the plug 17 clears the die 11- and the mandrel can be swung upwards to the broken-line positionof FIG. 1 for the application of a new workpiece to the mandrel or the reapplication of the workpiece just drawn thereto for another drawing operation.

The cylinder 13 is relatively long, being somewhat longer than the portion of the workpiece 15 being subjected to a drawing operation. The cylinder 13, as previously described, is movable along the rod 2-3 over the stationary piston 12; The cylinder is of the doubleacting fluid-pressure type, being supplied at both ends at opposite sides of the piston 12 with pressure fluid such as oil, through lines 48 and 49 connected through a 4-way 3-position valve 50 with pressure and exhaust lines 51 and 52 of a pump 53. The lines 48 and 49 are connected to the lower side of the cylinder 13 near its ends and extend downwardly therefrom through the space formed between the lower edges of the side members 1-8. In the position of the valve 50 of FIG. 1', the pressure and exhaust lines 51 and 52 are connected with one another so that the pump 53 by-passes the cylinder 13, and the cylinder is held against movement because pressure fluid can neither escape from nor enter the lines 48 and 49. When the valve- 50 is rotated counterclockwise from the position of FIG. 1, line 48 is connected with pressure line 51, and line 49-VVltl1 exhaust line 52, so that the cylinder 13 moves to the left. When the valve 50 is turned clockwise from the position of FIG. 1', line 49 is connected with pressure line 51, and line 43 with exhaust line 52, so that the cylinder 13 moves to the right.

The over-all length of the drawing apparatus, i.e., of the frame 10, is only a little more than twice that of the workpiece-15. This saving in length is made possible, because the movable cylinder 13 carries at one end the workpiece gripper 14 and is in side-by-side coextensive relationship with the workpiece 15. Stated in another way, the gripper'14 is attached to that end of the cylinder 13 which is displaced from the other end in the same direction the gripper moves in going away from the die 11. Thus, as seen in FIG. 1, the gripper 14 moves to the right away from the die 11, and the gripper is attached at the right end of the cylinder 13.

The apparatus of the present invention may be used to draw tubes or rods of. steel, zirconium alloys, copper alloys, and aluminum alloys to reduce the diameter of the rods or tubes in one or a number of passes.

It is also understood that the invention is not to be limited by the details given herein but that it may be modified within the scope of the appended claim.

What is claimed is:

Apparatus for drawing a tube of a given length, comprising' a frame approximately twice as long as the tube, a die mounted on the frame approximately at its center, a rod' extending the length of the frame and having its ends fixed thereto, a single piston fixed to the rod approximately at its center, a, single fluid-pressure cylinder embracing the piston and extending lengthwise of the rod, the cylinder being long enough to contain about half the length of the rod, a pair of opposed longitudinal ways secured to the frame and extending substantially the entire length thereof, a. pair of opposed shoes secured to the cylinder and extending substantially the entire length thereof, the shoes slidably engaging the ways for supporting the cylinder on the frame, a gripper for the tube shiftable in a certain direction lengthwise of the rod and cylinder from a position of adjacency to the die to a position of remoteness from the die, for pulling the tube through the die, the gripper also being shiftable in theopposite direction from the position of remoteness to the position of adjacency, means fixing the gripper only to that end of the cylinder which is spaced from the other end of the cylinder in the said certain direction, means for supplying pressure fluid to the cylinder to shift the same and the gripper in the said certain direction and the opposite direction, and a mandrel having a free end adjacent the die and the opposite end connected to an end of the frame, the mandrel extending in the said opposite direction from the said free end to the said opposite end, the mandrel being about half as long as the frame and supporting the tube during its passage through the die.

References Cited by the Examiner UNITED STATES PATENTS 2,550,925 5/51 Weimer 92-117 FOREIGN PATENTS 782,636 9/57 Great Britain.

CHARLES W. LANHAM, Primary Examiner. 

